An introduction to some of the biggest, heaviest and deadliest machines ever developed and built for very specific "mega tasks."

Muscle machines get the job done when it comes to towing equally heavy-duty vehicles; these high-powered specialist tow units rescue and retrieve massive military vehicles, push the world's largest aircraft, and transport huge rockets.

Thanks to six powerful turbines, the Antonov An-225 flies loads of up to 250 tons; the plane was originally destined to transport the Soviet space shuttle Buran back to Kazakhstan; when the space program ended, it was converted into a cargo plane.